Magnetic domains in spinor Bose–Einstein condensates

Michał Matuszewski, Tristram J. Alexander, and Yuri S. Kivshar

Nonlinear Physics Center and ARC Center of Excellence for Quantum-Atom Optics, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200, Australia
E-mail: ysk@internode.on.net

Received December 14, 2009

Аннотация

We discuss the structure of spin-1 Bose–Einstein condensates in the presence of a homogenous magnetic
field. We demonstrate that the phase separation can occur in the ground state of antiferromagnetic (polar) condensates, while the spin components of the ferromagnetic condensates are always miscible, and no phase separation occurs. Our analysis predicts that this phenomenon takes place when the energy of the lowest homogenous
state is a concave function of the magnetization. We propose a method for generation of spin domains by adiabatic switching of the magnetic field. We also discuss the phenomena of dynamical instability and spin domain
formation.